Unlock All Songs
At the "Rock Band" title screen press [Start] and then press [Red], [Yellow], [Blue], [Red], [Red], [Blue], [Blue], [Red], [Yellow], [Blue]. This will unlock all songs but you won't be able to save the game.

Hints

Achievements
Complete each of the following achievements below to get the allotted gamerscore:

Don't Lose Fans (After Failing a Song)
If your band fails a song in Band World Tour mode you would normally lose fans. Instead, unplug one of your wired instruments and, with a different instrument controller, and go to "Return To Main Menu". This will exit out of your career and dump you back to the Main Menu. Go back to your Band career and you will notice that you haven't lost any fans!